gst: utils: Add simple scoped lockers for GMutex and GRectMutex

While GLib has locker implementation already using g_autoptr(), recursive mutex
locker was only introduced in recent GLib. Implement a simple locker for GMutex
and GRectMutex in order to allow making locking simpler and safer.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/gstreamer/gstlibcamera-utils.h

@@ -16,4 +16,54 @@
 
 GstCaps *gst_libcamera_stream_formats_to_caps(const libcamera::StreamFormats &formats);
 
+/**
+ * \class GLibLocker
+ * \brief A simple scoped mutex locker for GMutex
+ */
+class GLibLocker
+{
+public:
+	GLibLocker(GMutex *mutex)
+		: mutex_(mutex)
+	{
+		g_mutex_lock(mutex_);
+	}
+
+	GLibLocker(GstObject *object)
+		: mutex_(GST_OBJECT_GET_LOCK(object))
+	{
+		g_mutex_lock(mutex_);
+	}
+
+	~GLibLocker()
+	{
+		g_mutex_unlock(mutex_);
+	}
+
+private:
+	GMutex *mutex_;
+};
+
+/**
+ * \class GLibRecLocker
+ * \brief A simple scoped mutex locker for GRecMutex
+ */
+class GLibRecLocker
+{
+public:
+	GLibRecLocker(GRecMutex *mutex)
+		: mutex_(mutex)
+	{
+		g_rec_mutex_lock(mutex_);
+	}
+
+	~GLibRecLocker()
+	{
+		g_rec_mutex_unlock(mutex_);
+	}
+
+private:
+	GRecMutex *mutex_;
+};
+
 #endif /* __GST_LIBCAMERA_UTILS_H__ */